Successful controlled adhesion without the use of glues or other adhesives remains a desirable goal in many applications. What might be considered a success in controlled adhesion can be defined as a technology that is controllable, reliable, safe, and robust enough to provide high mechanical pressure with electrical control. In some cases, it may be required to provide this mechanical pressure on a sufficient range of ordinary and every day materials. Such ordinary materials can ideally include those having wet, dusty, highly sloped and/or slippery surfaces. Traditional controlled adhesion technologies, such as chemical adhesives and suction cups, suffer from various drawbacks, including permanency, damage to or residue left at the applied surface, leaks, and a limited effectiveness on wet, dusty or irregular surfaces, among others.
The recent use of electroadhesive forces or electrostatic clamping as an alternative in controlled adhesion applications has proven to be advantageous on several levels. Such electroadhesive forces can be adapted to provide controlled adhesion on an electrically controllable basis without leaving residues or damaging surfaces. They can be fast acting in both on and off states, repeatable and strong, thus allowing repeatable modulation of material properties. Furthermore, a wider variety of dusty, slippery or irregular surfaces can be used with electroadhesive forces without detracting from a useful controlled adhesion outcome.
Of course, the use of electroadhesion, electrostatic clamping, or reversible electrostatic forces for mechanical materials requires the introduction of electricity, which can result in issues with safety, short circuiting, and other problems that are often associated with electrical charges. For example, significantly large voltages and electrical fields tend to be needed in order for a suitable level of electroadhesive or electrostatic forces to be generated. Also, the general use of and ready manipulation of multiple electrodes can present user safety issues, such as where untrained operators are able to use a commercial product that utilizes electroadhesive forces. Exposed electrodes may be a safety hazard in some situations. Traditional materials used for electrical applications can make it difficult to overcome such issues, resulting in product designs that can be overly cumbersome or bulky, so as to account for an appropriate level of user safety.
Although various materials for use in electroadhesive type applications have generally worked well, there is always a desire to provide alternative and improved materials. In particular, what is desirable are electroadhesive systems having materials that allow stronger electrostatic clamping at lower electrical field levels, while also providing for greater safety to operators using the systems. It may also be desirable to have materials that can produce strong adhesion on a repeatable basis using simple power supplies. Further, it may also be desirable to have materials where applied adhesion is released promptly when the clamping power being supplied to the materials is removed.